The present invention relates generally to wire-feed welding devices and, in certain embodiments, to methods and apparatus for controlling wire electrode advancement.
A common metal welding technique employs the heat generated by electrical arcing to transition a workpiece to a molten state, to facilitate a welding process. One technique that employs this arcing principle is wire-feed welding. At its essence, wire-feed welding involves routing welding current from a power source into an electrode that is brought into close proximity with the workpiece. When close enough, current arcs from the electrode to the workpiece, completing a circuit and generating sufficient heat to weld the workpiece. Often, the electrode is consumed and becomes part of the weld itself. Thus, new wire electrode is advanced, replacing the consumed electrode and maintaining the welding arc. If the welding device is properly adjusted, the wire-feed advancement and arcing cycle progresses smoothly, providing a good weld.
Traditionally, during a welding operation, an operator selects the level and types of resources provided to the weld location, depending, of course, on the particulars of the weld and the materials being welded. For instance, an operator may select between various kinds and sizes of wire electrode, ranging from the diameter of wire the electrode to the material the wire electrode is made of. Different kinds of wire electrode, however, perform well at different operational settings of the welding device. That is, different kinds of wire electrodes perform well within different voltage ranges and wire-feed speeds, for instance. For example, a given 0.023 inch mild-steel wire electrode may well perform at 17 Volts and with a wire-feed speed of 250 inches per minute, while a 0.035 inch mild steel wire electrode well performs at 19 Volts with a wire-feed speed of 230 inches per minute.
Conventionally, welding devices rely on the knowledge and acumen of the operator to select the most appropriate voltage and wire feed settings for the wire electrode being used and weld conditions. Unfortunately, in many cases, the weld operator is a novice to field, especially in the case of portable welding devices. If the operator does not properly adjust the voltage and wire-feed speed settings, the arcing may not be sufficient to produce a good weld, or a weld at all. Furthermore, in traditional devices, the wire-feed speed control and the voltage control are wholly independent from one another, thus making it difficult for the operator to adjust the both parameters while a weld is progressing.
Therefore, there exists a need for improved apparatus and methods for the control of wire-feed welding devices.